The FIA has reacted to suspicion that teams are changing the ride height on their cars after qualifying.

The governing body has acted following claims in Singapore that an unnamed team was adjusting the bib clearance between the end of qualifying and the race.

Such a move would be advantageous for a team seeking to change from the low-fuel set-up required for qualifying to the full fuel load at the start of the race.

Naturally, such a move would be illegal as the only aerodynamic change permitted between qualifying and the race is to the front wing.

"The aerodynamic set up of the front wing may be adjusted using the existing parts," sates Article 40.2 b) i of the Sporting Regulations. "No parts may be added, removed or replaced."

While 40.9 b) states that: "In order that the scrutineers may be completely satisfied that no alterations have been made to the suspension systems or aerodynamic configuration of the car (with the exception of the front wing) whilst in pre-race parc fermé, it must be clear from physical inspection that changes cannot be made without the use of tools."

It is believed that at least one team is circumventing this by allowing the necessary change to be made from within the cockpit - away from the stewards and rivals' prying eyes.

"Any adjustment to the front bib clearance during parc ferme conditions is strictly prohibited by the regulations," declared the FIA is a statement issued ahead of this weekend's United States Grand Prix.

"While we have not received any indication of any team employing such a system, the FIA remains vigilant in our ongoing efforts to enhance the policing of the sport," it added.

"As part of this, we have implemented procedural adjustments to ensure that front bib clearance cannot be easily modified.

"In some cases, this may involve the application of a seal to provide further assurance of compliance."

While the advantages of making such a change are obvious, so is the disadvantage if caught, especially as the title fight hots up, for breaking the rule would surely lead to disqualification.

It's understood that alarm over the issue was first raised via the FIA's open-source system, which is open to all the teams, suggested the ingenious means of circumventing the rule in a way that would not be picked up in post-qualifying scrutineering.